This proposal deals with patterns of cognitive deterioration in Alzheimer's disease, and irreversible dementing disease associated with diffuse, degenerative changes in the gray matter of the brain. It is now recognized that Alzheimer's disease accounts for at least one half the population diagnosed as having senile dementia, and for the majority of dementias arising before senescence. Yet, despite the pervasiveness of the health problem, and its devastating social consequences, the disease is barely understood. One serious obstacle to experimental investigation of this population is the diversity in the presenting symptomatology. We are proposing to work toward a much needed refinement in neuropsychological description by: 1. identifying subtypes within the Alzheimer's population on the basis of predominant cognitive impairment in the early stages of the disease; 2. subjecting to experimental analysis the language, memory, and visuospatial disorders in Alzheimer's patients whose predominant cognitive symptomatology lies in one or another of these domains; 3. exploring, in a series of longitudinal case studies, what significance, if any, these early profiles have for the subsequent course of the functional deterioration, for long term prognosis, and for the distribution of neuropathological changes in the brain.